Of the 160,000 new cases of colorectal cancer (CRC) diagnosed each year in the U.S., at least 15% have a hereditary component. Two well-defined syndromes, Familial Adenomatous Polyposis (FAP) and Hereditary Non-Polyposis Colorectal Cancer (HNPCC), account for up to 5% of the familial cases. Truncating APC mutations are responsible for FAP, and defective mismatch repair genes cause HNPCC. However, the genes responsible for the majority of the familial cases are unknown. There is a need in the art for additional tools and information for identifying familial cancer genes.